Two-cycle engine



W. A. EDWARDS. TWO-CYCLE ENGINE.

APPLICATION man luLY s. 191s.

Patented Sept. 21, 1920.

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UNi're 'STATE PATENT; orifice.

WILLIAM A. EDWARDS, F CHICAGO, ILLINOIS.

Two-CYCLE ENGINE.

Application sied July 8,

To all 'whore t may concer/n Beit known that I, WILLIAM A. EnWARDs,

i a subject of the King of Great Britain, re-

siding at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Two-Cycle Engines, of which the following is a specification.

This invention relates in general to gas engines and has more particular reference to the two-cycle type, the aim ofthe invention being to improve the construction and increase the eiiciency of this type of engine. One of the objections heretofore inherent in two-cycle engines is the diiiculty of prop- -erlyvscavenging the cylinders, or,l in other words, getting ridV of substantially all of .the burnt gases without permitting any of the explosive charge to escape through the exhaust port. Engines of this character now in use customarily have the inlet port to the cylinder and the outlet port located 0n opposite vsides of the cylinder, and the upper face of the piston is provided with an upwardly extending deflecting portion designed to deflect they incoming gases upvwardly away from the exhaust port with a view of having the burnt gases escape through the port before the incoming gases approach this port in their travel within the' cylinder. Experimentation, however, has conclusively proven that the deiector carried by the piston sets up such eddies and counter-currents in the incoming gasesin the cylinder that these gases instead of driving out the burnt gases ahead of them mingle with the burnt gases with the result that a portion of the explosivecharge is discharged with the burnt gases through the exhaust port and a considerable proportion of burnt Y gases, because of their mingling with the incoming gases, remain in the cylinder.. This mingling of the incoming and burnt gases obviously materially decreases the eflicient working of the engine.

My present invention contemplates delivering the explosive charge to the cylinder in such a manner that it will circulate within the cylinder in a predetermined path and drive the exhaust gases out ahead of it with-f out any appreciable mingling between the explosive and burnt gases, with the result that practically all o the explosive charge Specification of Letters Patent. Patented Sept-, 21, 1920.

1.916. Serial N0. 108,103.

is retained, thus filling the cylinder with a -pure explosive mixture which `results in a very high working eiiic'iency.

l It is customary, asis well known, in engines of this type to admitl the explosive mixture from the carbureter into the closed crank case communicating with the lower` end ofthe cylinderbeneath the piston', the gas beingvdrawn into the crank chamber upon the upstroke of the piston and be- -1ng compressed in thev crank chambery to about ten pounds (l0 lbs.) pressure upon the downstroke of the piston. The explosive charge under this slight pressure is then.

fore been delivered from the upper portion .of the crank case to the cylinder it is obvious that the lighter portions of the contents of the crank case are delivered to the cylinder while the heavier portions gradually settle in the bottom of the crank case until a considerable quantity is accumulated. The action of the crank arm in the case, when a suiiicient quantity of this heavy, rich mixture has accumulated, will carry a portion of it into the upper part of the crank case from which it will be drawnl as aslug of heavy, rich mixture into the cylinder. This slug is 'entirely too rich for proper explosive action, and the result is that' an imperfect explosion occurs which causes uneven running ofthe engine. The more frequently these heavy, rich slugs are delivered to the cylinder the more uneven'will be the operation of the motor, and even under the most' favorable conditions it is a well known fact that a.

two-cycle engine' will periodically .have one or more imperfect explosions which detract from the rhythmic,.ever\ an deicient opera tion of the engine.

My present inventionis designed to obvate this uneven running of-a two-cycle engine and to deliver to the cylinder a conltinuous mixture of even and uniform richness. In order to accomplish this result instead of drawing the explosive charge from the upper portion of the .crank case I prop'ose to take it from the lowest point in the crank case, so thatthe heavy, rich portions of the charge, instead of accumulating in the crank case and being fed to the cylinderl at irregular periods andin large slugs, are

continuously drawn from the crank case together with the other lighter portions of the mixture and are delivered to the cylinder at each reciprocation of the piston, with the resultl that the explosive charge delivered to the cylinder is always of an even and uniforml richness, which insures steady, uni-` form, even and elicient operation of the' motor.

In order to facilitate an understanding of my invention I have illustrated on the accompanying drawings one practical and preferred embodiment thereof froman inspection of which, when considered in connection with the following description, my invention and many of its attendant advantages should/be readily appreciated. Referring to the drawings,

Figure 1 is a vertical sectional view through one cylinder of a two-cycle engine embodying my invention, the piston being shown in its uppermost position; and

Fig. 2 is a similar view showing the piston in its lowe'rmost position.

On the drawings reference character 3 inf dicates generally the cylinder walls of a two-A cycle engine provided with the usual water jacket 4. The top or cylinder cap 5 may be of any preferred construction and is preferably equip`ped with the water cooling chambers 6 and the customary tapped opening 7 for"(a spark plug, this cap being 'secured in position by the usual studs or stay bolts 8.

The crank case, designated generally by ref- A erence character 9, is of the closed type, as

ymeans of a link or piston rod 12 with the crank shaft 13 suitably mounted in bearings', not shown, and equipped with the usual fly-wheel 14.

' The explosive mixture is supplied from a carbureter (not shown) to the crank case and the cylinder beneath the piston throughv a laterally opening port 15, this port being openedand closed by the piston and so lo- Vtion of its downward stroke.-

cated that it' will be fully-'opened when the" piston is at the upper endA of its stroke, as .shown in Fig. 1, and will be entirely closed when the piston. has completed/a limited por; A. Partial vacuum vwill be created in the crank chamber, as is well understood,lby the piston on its upward stroke and as soon as theport 15 is opened the explosive mixture will rush in and ll the crank ,chamber andthe lower portion of the cylinder so that when the piston is moved downwardly .the mixture trapped in the crank case when 'the port 15 is closed will be compressed to about ten pounds (10 lbs.) pressure in the usual manf ner.

.lighter portions of the mixture are nor.

mally delivered to the cylinder, as has been previously explained, is delivered from the crank chamber through a passage 16 which communicates with the crank chamber at its bottom or lowest point thereof, as indicated by reference character 17. The heavy portions of the mixture which have a tendency to settle to the bottom of the crank chamber are,.accor dingly, delivered through the passage 16 at each reciprocation of the piston and are discharged into the cylinder above the piston through the inlet 4port 18. It will be observed from Fig. 2 that the inlet port is fully opened when the piston has reached the downward limit of its stroke, and the explosive gases are thereupon admitted under y.pressure and travel directly The charge in the crank case instead of being' delivered to the upper portion of the acrossy the cylinder in a slightly upward dii rection due to the inclined position' of the the opposite wall by which they are delected upwardly and then laterally by the cylinder cap and finally downwardly along the` wall through which they first entered, thus making a complete circuit of the cylinder chamber, driving the exhaust gases before them out through the exhaust port 19 which is located directly above and in alinement longitudinally of the cylinder with the inlet port 18. From the exhaustport the burnt gases are discharged through the usual exhaust pipe 21. l

Exhaustwe tests have thoroughly demonstrated that by locating both the inlet and exhaust po-rts on the same' side of the cylinder in proximity to each other with the exhaust port above the inlet port'and in alinement therewith longitudinally of the cylinder the exhaust gases are driven out by the incoming gases which travel in aclearly delined circuit through the cylinder chamber, and the cylinder is thoroughly scavenged and freed fromthe burntvgases so that practically a pure charge of explosive mixture 105 upper end of the passage lvuntil they strike l ton so that sufficient the passage 16 relatively low cost.

variation as to ports, a crank case,

` is left in the cylinder for effective working purposes. The relative location of the inletand exhaust ports causes the exhaust port to be opened first and time is' afforded for the escape of the exhaust gases while a lesser but suiiicient time is afforded for the incoming gases which are admitted under pressure, to completely charge the cylinder.

It will be manifest from the foregoing that l. have provided an engine which is highly eiiicient in" operation, since it delivers a uniform mixture `at all times to the cylinder without any intermittent slugs of 15 extremely rich mixture which have hereto-l fore been characteristic of two-cycle engines, and that by my peculiar arrangement of the inlet and outlet ports and as the result of the inclined position of the upper end of I am enabled to thoroughly scavenge the cylinder of the burnt gases and to completely charge the cylinder with an explosive mixture undiluted or diminished in quality by the burnt gases. l*`urthermore,

.25 it should be noted that my engine is entirely devoid of valves and valve mechanisms, since all of the ports, both inlet and exhaust to the cylinder and the inlet to the crank chainber are automatically opened and closed in- 30 predeterminedtim'ed relation by the piston itself. It should be obvious therefore that my invention is not only highly eflicient in operation but the engine is extremely simpler in construction and can be manufactured 'at While l have illusytrated an'd described one preferred embodiment ,of my invention it should be understoodthat the structural details disclosed are capable of considerable modification and the size, shape, proportion and arrangement of the various parts without departing from the essence of the invention as defined in the following claims.

I claim:

1.` A two-cycle engine, comprising a cylinder provided with inlet `and exhaust ports, v a piston devoid of gas deflecting provisions on its upper face arranged to reciprocate in said cylinder so asvto open and close-said and means including a passage having an upwardly inclined delivery end for delivering an explosive charge from saidcrank case through said 4 .inlet port directly against the opposite side Iwall of the cylinder and in an upwardly inclined direction below the longitudinal center of said cylinder.

2. A two-cycle engine, comprising a cylin- ,der provided with an inlet and an exhaust port disposed in alinement longitudinally of the cylinder on one side thereof and vhaving .an inwardly, convex cylinder head, and.

means for delivering an explosive charge closed last by the pisthrough said inlet port against the opposite .side wall of the cylinder between the plane of said port and the longitudinal center of said cylinder'at an angle to the axis ofthe cylinder.

3. A two-cycle engine, comprising a cylin- .der having an inwardly convey cylinder head, a crank case, and means for delivering an explosive charge -from said crank case into said cylinder at an angle to the longitudinal and transverse axes thereof so that the charge is projected against the opposite cylinder wall above the port and below the longitudinal center of the cylinder, said cylinder being provided with an exhaust port adjacent to the point of admission of said charge.

4. A two-cycle engine, comprising a cylinder, a crank case connected thereto, a fiat toppedpiston reciprocable in said cylinder, v

said cylinder being provided with lan admission port controlled by said piston so`as to admit gas to the crank case when the piston is in uppermost position and also provided with intake and exhaust por'ts located at one side of the cylinder in alinement longitudinally of the cylinder and controlled by said piston so as to be opened when the piston is vin lowermost position,

and a passage leading from the lowest point of the crank case to said inlet port.

5. A two-cycle'engine .comprising a cylinder, a piston therein, a closed `crankcase communicating' with said cylinder below said piston, means for supplying an explosive charge to s aid crank case, and means for conducting said charge from the lowest poi t -of the crank case to said cylinder above the piston. i

6. A `two-cycle engine comprising a cylinder communicating at its lower end with 105- a closed crank case, a piston-in said cylinder, a gas supplying passage `opening into said cylinder through which an explosive charge is supplied to the crank case, said passage being arranged to be opened when the piston reaches the upper limit 'of its explosive charge from theflowest point of Y said crank case to the explosion chamber Aof the cylinder, saidpassage being adapted to communicate with the explosion chamber when said piston is at the lower limit of its travel.

'7. A two-cycle engine, lcomprising a cyl- ,I

inder, a substantially flat-topped piston arranged to reciprocate therein, a crank case,

vmeans for admitting vfuel to said crank case upon the up-stroke of said piston, and means outside the cylinder chamber for delivering an explosive charge `from the. crank case 110 travel, and a passage for conducting said rom the top thereof so that said charge is caused to follow the contour of the cylinder and drive out'\ the exhaust gases therefrom.

8. A two-cycleengine comprising a cylinder yprovided with exhaust and inlet ports; a fiat-topped piston. therein, a crank case, and a passage connecting the crankcase Leashes vvith saidfcylinder inlet port, said passage and vinlet port being upwardly inclined near their delivery end to deliver the explosive charge;finto saidl cylinder in an upwardly WILLIAM A. EnWARDs. 

